.TH std::make_any 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::make_any \- std::make_any

.SH Synopsis
   Defined in header <any>
   template< class T, class... Args >                                \fB(1)\fP \fI(since C++17)\fP
   std::any make_any( Args&&... args );
   template< class T, class U, class... Args >                       \fB(2)\fP \fI(since C++17)\fP
   std::any make_any( std::initializer_list<U> il, Args&&... args );

   Constructs an any object containing an object of type T, passing the provided
   arguments to T's constructor.

   1) Equivalent to return std::any(std::in_place_type<T>,
   std::forward<Args>(args)...);
   2) Equivalent to return std::any(std::in_place_type<T>, il,
   std::forward<Args>(args)...);

.SH Example


// Run this code

 #include <any>
 #include <complex>
 #include <functional>
 #include <iostream>
 #include <string>

 int main()
 {
     auto a0 = std::make_any<std::string>("Hello, std::any!\\n");
     auto a1 = std::make_any<std::complex<double>>(0.1, 2.3);

     std::cout << std::any_cast<std::string&>(a0);
     std::cout << std::any_cast<std::complex<double>&>(a1) << '\\n';

     using lambda = std::function<void(void)>;

     // Put a lambda into std::any. Attempt #1 (failed).
     std::any a2 = [] { std::cout << "Lambda #1.\\n"; };
     std::cout << "a2.type() = \\"" << a2.type().name() << "\\"\\n";

     // any_cast casts to <void(void)> but actual type is not
     // a std::function..., but ~ main::{lambda()#1}, and it is
     // unique for each lambda. So, this throws...
     try
     {
         std::any_cast<lambda>(a2)();
     }
     catch (std::bad_any_cast const& ex)
     {
         std::cout << ex.what() << '\\n';
     }

     // Put a lambda into std::any. Attempt #2 (successful).
     auto a3 = std::make_any<lambda>([] { std::cout << "Lambda #2.\\n"; });
     std::cout << "a3.type() = \\"" << a3.type().name() << "\\"\\n";
     std::any_cast<lambda>(a3)();
 }

.SH Possible output:

 Hello, std::any!
 (0.1,2.3)
 a2.type() = "Z4mainEUlvE_"
 bad any_cast
 a3.type() = "St8functionIFvvEE"
 Lambda #2.

.SH See also

   constructor   constructs an any object
                 \fI(public member function)\fP
   any_cast      type-safe access to the contained object
   \fI(C++17)\fP       \fI(function template)\fP
